Changes within deep regions of the brain can now be visualized at the cellular level, based on research on mice, which was funded by the National Institutes of Health. Published Sunday in Nature Medicine, the study used a groundbreaking technique to explore cellular-level changes over a period of weeks within deep brain regions, providing a level of detail not possible with previously available methods.

Investigators focused on two brain regions within the study, the hippocampus and striatum. The striatum, a brain region important for motor function and habit formation, is also a major target for abused drugs. Some researchers believe that a shift in activity within the striatum is at least partly responsible for the progression from voluntary drug-taking to addiction. This new technique could allow a better understanding of how these processes occur at the cellular level, leading to insights into mechanisms underlying addictive behaviors.

"The results should now allow neuroscientists to track longitudinally in the living brain the effects of drugs of abuse at the levels of neural circuitry, the individual neuron, and neuronal dendrites," said Dr. Mark Schnitzer, corresponding author for the article. "For example, our imaging methods work well in the dorsal striatum, which we have followed with microscopic resolution over weeks in the live brain. This should permit researchers interested in the reward system to address a range of issues that were previously out of reach."